Erasing only free space

With regard to an iBook G4, OSX 10.5.8 - would I be correct in thinking that the "Erase Free Space" command does just and only that, and does not affect the OS, installed programs, or all non-deleted data ? In other words it is safe to run on the iBook which will remain in use.

Yes. Back up the files anyway.
(103875)

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How do I erase the free space on macbook pro retina?

I went to erase the free space on my MacBook Pro Retina in the Disk Utility but it says not available for this type of drive. Is there a way I can get around this?

You can't use Disk Utility to securely erase a Solid State Disk drive, because of the fact that SSD's have limited write capability, unlike hard drives, thus have to protect the sectors from as little writes as possible.
In fact TRIM (wear leveling) is enabled to write new data to the least used sectors on a SSD each time.
The NSA guidelines for secure data destruction on SSD's is to grind them into a fine powder.
If you don't require this level of data destruction, you can do this trick below, but not often or you'll premaurely wear out your SSD.
Finder > Duplicate a small file repeatly in a folder until slightly more than 50% of the remaining free space on the SSD is used up, (use Activity Monitor) then delete this folder.
Then duplicate a different small file repeatly in another folder in the same manner.
What this will do is, because of the small file, OS X will fill the smallest unused spots on the SSD, the duplicates will fill the remaining free space half way, then the second folder will (because of TRIM) fill the other remaining 50% of the free space.
You can't fill your boot drive or the machine can refuse to function or boot, but because of the wear leveling this should overwrite all your available free space on the SSD once.
If you have a laptop and TimeMachine, there is a hidden database on the boot drive which will store a copy of the deleted data.
Then there is "versions" and it's possible a copy of the deleted data is stored in that cache file still on the SSD.
I can advise how to delete the TimeMachine backup file on the boot drive, but not the "versions" database or what it contains.
How do I securely delete data from the machine?
If your really paranoid it's likely best to reformat the entire MacintoshHD partition from recovery and then with a new user, then do the Finder > Duplicate procedure to overwrite the deleted data off the SSD, this way the "versions" and TimeMachine databases are also overwritten.
Nothing is safe anymore.

Boot, shutdown slow after erasing disk free space

On the advice of a friend I used Disk Utility to erase free space on my MacBook Pro disk. Used the 'zero' option. At the end of the erase procedure it tried to run a routine to create a 'backup file'. There was a "Skip" button and because it was late at night I skipped it. Still took 10 minutes to complete. Since then it takes almost 2 minutes for the thing to boot and to shutdown - was approx 30 seconds for boot and maybe 10 or 15 for shutdown previously. Once it does boot, it takes even longer to find my wireless network. I tried verifying the disk (it's OK) and repairing permissions, both to no avail. I have no apparent battery issues. Anyone have any other suggestions before I start from scratch? TIA.

Yes, I tried DiskUtiliy from the CD, didn't work. Eventually gave up, backed everything up and re-installed OS X. After downloading and installing all the updates it now boots and shuts down as expected. I think I'll stay away from the Erase feature...

I thought I was creating free space by erasing free space using disk utility but what I really did was literally ERASE MY FREE SPACE on my Macbook Pro 10.8.4 and all I want to know is what to do to recover my free space?

When I click on ABOUT THIS MAC and then on STORAGE it shows that I have like 700 gb of "OTHER" in yellow and all I want is for the yellow to disappear and have all my free space again! please someone help me
<Edited by Host>

Your free space hasn't gone anywhere. This is simply the initial result of the process. However, your free space should be there once you need to use it.
What is "Other" and What Can I Do About It?- Apple Support Communities

Errors upon erasing free space

I have been experiencing particularly bizarre errors since switching to Mac. Two of the strangest are related to erasing free space.
I wasn't aware that OS X could erase free space on its own, until I read the security guide, so I first purchased Shredit X. It worked the first time. The second time, it did not free up the space after the shred. I couldn't even close my programs without resorting to the command line, but I eventually got it to shut down without a hard reset. As I was logging off, the "Reclaiming disk space" process, or whatever it's called, ran as usual, and it appeared to work. My disk space was back to normal. A few days later, I tested it again, to see if it was a fluke, and it did the same thing. I have spoken with the company, and they're not sure what caused it. So I decided to go with Disk Utilities instead.
I started the process last night, and left it going overnight. This morning, I checked to see if it was finished. The login screen that appears after the computer has slept worked fine. However, it was a different story after I logged in. I could not hit any key on the keyboard, and they would trigger the beep that occurs when you hit an invalid key. I could not left-click. The only input that worked at all was a right-click, and it only worked on the application bar at the top of the screen. I was unable to shut down, because I could not close dialog boxes, so I had to hard reset.
It would be nice if there was some explanation for either of these...

<EDIT>I don't know if I made this clear enough in my original post: The computer works fine after the restart, and I am even posting from the computer in question right now. The problems with input lasted only between the time the free space wipe finished, and the time when I had to hard reset.</EDIT>
The Knowledge Base article about Disk Utility to which you linked stated this: "When possible, disk permissions should be repaired while started up from a Mac OS X volume (hard disk) that contains updated Mac OS X software, instead of a Mac OS X installation disc." It also mentioned loss of software updates if it was not run from the startup disk. And so, I am a bit leery of running it from the install disk...
I had verified disk permissions a short while ago, so I didn't expect anything out of the ordinary. I was wrong, and there was quite a bit of weirdness with the permissions, almost all of it about not expecting ACL in "System/Library/User Template". I tried to repair disk permissions, and everything looked like it went okay. But when I verified again, it apparently didn't actually repair them.
Will running Disk Utilities from the install disk cause me to lose any data? I have no backups, as I don't own an external hard drive, so I really wouldn't want to lose anything. In particular, my collection of images of album covers, my music collection, my own recordings, and the metadata on the music are all things I'd rather not part with. Should I even be worrying about this?
I'm also not sure what the connection would be between my problem and disk permissions. Could you explain that a bit? I still have no idea why erasing the free space messed with my input devices.
Sorry for the extra-long post, but I figure getting as much info out as possible could help to solve the problem.
That animated image of a bug in your signature is amusing, by the way.
Message was edited by: Your New Favorite

Does Erase Free Space Degrade Hard Drive?

I've noticed with my macbook that erasing free space takes bloody ages, 2 hours for 1 pass, 18 for 7 pass, 3 days for 35 pass.
This seems like an awful long time to have your laptop sitting on and open let alone your disc spinning and writing. Does this process degrade, slow down or have any seriously harmful side-effects to your hard drive?

My question is simply, 3 days of nonstop writing to zero out free space from insecure trash empties (some people might have important goverment docs, I don't know) seems like long enough to burn out your drive in one single process, no?
No, not unless the drive is already perilously close to failure when you begin the process.
And with their awkward sleep with lid closed standard feature, you have to leave the laptop sitting open and running... 3 days, surely that'll cause some problems?
Are you concerned that running the computer with its display open is hazardous to its health? Nothing could be farther from the truth. It cools itself more efficiently with the display open than with the display closed. Apart from that, having the lid open or closed makes no difference at all.
Out of curiosity, what do you consider "awkward" about having the computer go to sleep when you close the display?
I agree with Michael that if one were to do a 35-pass erase of free space every week, or even every month, it would become a significant factor in the longevity of the drive. But doing it a small handful of times over the life of the drive — say perhaps once a year — would account for only an insignificant portion of the drive's total use/operation.

Undo erase free space?!?!?!

i screwed up my powerbook, i have a capacity off 74.4 gbs on my hard drive and i ran erase free space and now i only have 244.0 kb, how do i get my hard drive space back??? please help im having a nervous breakdown.

A similar problem came up in the unix section of this site a while ago. Apparently, "erasing" the free space in "Tiger" is performed by basically making a file representing the free space, overwriting that file, then deleting the file. The problem in that case was that the user's battery ran out before the "delete" step so they were stuck with the massive file left on the hard drive (in their case, they couldn't even boot).
To see if you are affected by a similar problem, try logging in to an "admin" account, opening "/Applications" > "Utilities" > "Terminal.app" and entering this command:<pre>sudo ls -lh /private/var/root/Library/Caches/TemporaryItems"</pre>At the prompt, enter your "admin" password. The output should contain a listing of the contents of the directory where the temporary files were saved in the earlier case...

URGENT: Erase Free Space

I filled up my computer's memory completely. Then I deleted a few GBs of files to make space for new files I need...but of course the computer doesn't recognize that files have been deleted. So I ran the Disk Utility "Erase Free Space"...but it immediately went into error: "Unable to create temp file".
So I don't even have the space to create the temp file to erase the free space. What do I do now?
Thank you for your help
iBook G4 Mac OS X (10.4.8)

When you deleted those files, did you use "secure empty trash"? There
may be other trashes in the system that also hold stuff you could remove.
By using a utility such as What Size, you can hunt down where items are
located in the hard drive, and carefully consider removing them. This can
do it. Of course, important OSX system files and application support
stuff should be left alone; and if you move/remove iTunes music files,
they need to be handled carefully. Plus duplicates may remain.
If you can't save your data to a DVD or CD-R media, you may have to get
and use an externally enclosed hard disk drive (preferrably a FireWire unit)
so you can move or copy/clone files from your computer's hard drive. There
are a few good disk clone utilities, super dooper is popular and carbon copy
cloner is good. An external FW HDD of larger capacity than your 'Book's
hard drive could be partitioned to hold several entire computer drive clones.
In order to erase free space, you may have to use a third party disk utility; and
some of these could result in loss of data, so to backup your stuff first is
the best advice and course of action before doing much else. If you make
and use a clone utility, be sure the copy/clone's files you want to keep are
accessible. If you seek to make your entire 'Book's HDD 'clone' over to a
second and external FW drive, be sure to run "repair disk permissions" on
the original drive & read the instructions thoroughly before using a clone utility.
By making a complete computer drive clone to an external FW hard drive
you can then plan on a total erase (zero-data using disk utility options)
and reformat the computer's drive; this will get rid of everything and leave
the drive unpartitioned and without fragmentation. Free space without any
fragmentation or artifacts, then either re-clone your 'Book's system and
all your stuff back over, or only move the important things back to it.
The hard drive's capacity is sometimes mistakenly called "memory" and
it is confused with RAM; but I know what you mean in the context given.
Sometimes, you can restart your computer after deleting stuff
and it may see the stuff as "gone" then. Also, you can see if using
"repair disk" from the booted disk utility and also repair disk
permissions, will help. Working on the root or base level of the
hard drive can damage important files, so hopefully you can get
that free space to show and work for you.

SSD - Disk Utility - Erase Free Space

Hi Community,
does the function in disk utility, which erases the free space by writing zeros into it, in context to a SSD drive the same like a block refresh which some drive vendor utilities does to increase the write performance? Or is a block which contains only zeros not really empty for the SSD controller?
Thx & Bye Tom

I am guessing a little here, but I suspect that "Trim" support ensures that data in free space can't be reaccessed once the files are deleted.
Another guess is that erasing the SSD free space may not be a great idea from the point of view of unnecessary writes and also filling the entire usable space up with what may appear to be data.
We are also discussing this subject in a German newsgroup and there we came to the result that the only way to inform the SSD-controller that the content of a specific block is invalid, is either to overwrite a specific logical address, so than the controller knows which physical blocks are invalid or to send the TRIM command.
To write zeros into the empty space is from the controllers point of view only content and will result in a full SSD drive afterwards. As longer I think about this as more I belief that this is correct and the use of the disk utility to refresh a SSD drive isn't the best idea... ;-)
Bye Tom

Disk Utility - Erase Free Space

Hey Forum,
I am using mac snow leopard on my macbook and I wanted to erase the free space on my hard drive, so is the zero-out free space enough, or do I need the 7-pass erase free space. I just wanted more disk space, thats it. So can anyone tell me what are each options for? And do i need to 7-pass erase if i just wanted more disk space?
I await your favorable replies.
Thank you.
Regards.
Ala.

As The hatter says, the erase free space option has nothing to do with creating more free disk space -- the space is already free.
If you are confused about this, just open Disk Utility to the "Erase" tab & click the purple question mark at the bottom of the window. This will open Disk Utility Help to the topic *Erasing disks*. Refer to the last subject, *Securely erasing empty space* & if necessary click the link below it to go to the help topic *Erasing free disk space*, which explains this function in more detail.
FWIW, should you ever need to use this security function, a one pass secure erase is probably adequate to make the data unrecoverable.

Erasing Free Space on boot drive

I am getting ready to sell my older Mac Book Air with a SSD. I would like to erase all free space on the drive to assure that any confidential data I hadn't securely deleted earlier is not recoverable. In my most recent cleanup, I moved all my own files and installed apps to the trash and attempted to empty the trash securely. When the number of files to be removed was down to 30,000 (from neaerly 100,000) it stopped securely removing them. I rebooted several times and those files were still in the trash. I attempted each time to securely empty the trash. It would pop up the progress dialog box but would immeidately close it cleaning up nothing. Finally, I switched to non-secure and emptied the Trash.
I've done to the Disk Utility, selected the SSD Drive (Macintosh HD) and selected the Erase tab. The Erase Free Space button is disabled. How can I securely clean up the free space so that whoever buys the system will not be able to recover whatever, confidential data may still be hanging around in the free disk space list?
Thanks,

read this article, it is outdated, but the info in it is still relevant: http://support.apple.com/kb/TA24002. Do a 7 pass erase. That conformed to the U.S. Department of Defense's security procedures until they changed their rules to that of completely destroying hard drives physically instead.

Erased free space in Disk Utility, and after it finished it kept a DMG there.

I erased free space in Disk Utility, and after it finished it kept a DMG there called "DeveloperDiskImage.dmg", why is it left behind? can it be deleted? how? if erasing free space is supposed to help get memory and remove all the files truly, it shouldnt be creating anything, it created a DMG at the start, but it went away, after a hour and a half it made the DeveloperDiskImage, i went to eat dinner and when i came back it was done but that was left.

Delete it. Erasing the free space isn't supposed to free up any space; it's there in case someone deleted a file insecurely when they meant to securely delete it.
(65417)

Disk Utility: erasing free space

I read a recent magazine feature about file security and, based on its advice, clicked the Erase Free Space button in Disk Utility to overwrite the free space on my hard drive.
Everything ran smoothly until the last minute, when the countdown switched to "Creating Temporary File". After five minutes, a dialog box appeared warning me that the start-up disk was almost full.
I'm not concerned that I might lose material on the start-up disk since I have an external drive as a complete bootable back-up of the hard drive. But:
1. What's is being created in this temporary file and why?
2. How do I get Disk Utility just to erase the free space next time and not bother with the temporary file that seems to fill all the space (and more) that has just been cleaned?
Thanks in advance.
PowerMac G4 867MhZ Mac OS X (10.4.6) iGB RAM
PowerMac G4 867MhZ Mac OS X (10.4.6) iGB RAM

You're Welcome Norman!
I'm happy that I could help!
Also, I notice that you have not marked your topic as answered, nor utilized the Helpful or Solved options. That may be intentional, but, if you are not aware of the benefits, of using that function, here is some information.
When you mark the appropriate posts as Helpful (5 pts) 2 available, or Solved (10 pts) 1 available, you are Thanking the contributors, by awarding them points.
In threads with multiple replies, it also alerts other readers, to which answers may have been helpful, or solved the issue.
This info, and more, can be viewed by clicking on
? Help & Terms of Use, located under your login name, on all "Discussions" pages.
Specifically What are question answers?.
The Helpful and Solved buttons, that award points, are to the left of the Reply button in each response.
These are not the same as these Which do not award points, as explained Here.
Thank You, for considering extending the courtesy, of awarding stars in Discussions, as this is not a requirement, nor mandatory.
ali b

Erase Free Space SCARE !!!

I decided to erase the free space (50GB) on my eMac using Disk Utility.
On selecting "Erase Free Space" all seemed well and I was given an estimated time of 20 minutes.
At the end of this time, the progress bar was near the end of the line when a new message appeared which said something like "Writing or creating file".
This continued for several minutes and the progress bar did not appear to be moving so I pressed the "Skip" button and for a few more minutes nothing seemed to be happening. It certainly didn't stop.
In desperation I quit Disk Utility even though a warning came up saying it COULD leave my HD unusable.
I discovered that my HD had 0KB of free space.
Using "WhatSize" I found that the missing 50GB were in a "Temporary Items" file.
I tried to trash them but was told one of the items was in use, so I restarted the computer and was able to empty the trash.
The whole computer was fine and back to normal.
However, it was a worrying experience.
What did I do wrong ?
Ian.

I think you'll be fine. All that "erase free space" process does is eliminate all your free space with a big file, then delete that file. If you are really paranoid, you can have it overwrite with random data - seven times. Yes, it can take forever. Because it does fill up your drive, you shouldn't do anything else while it is running. Finally, there is a possibility that your machine could crash if your hard disk is bad. Part of your free space could be a bad place on your disk that you have just never accessed before. This is not likely, but possible.
In the future, you should consider creating a large encrypted disk image for sensitive files. Do not use FileVault. Just create a single disk image that you mount when you want to access your private files. You can even create unencrypted aliases to encrypted files inside the image. Make sure you have secure virtual memory turned on too. If you delete a file from that image, it is already encrypted so nothing to worry about. It is possible that some applications could create temporary files in unencrypted space, but you can't do much about that. This is about as good as you can get.

Erase free space fails

I am trying to erase the free space on my hard drive, but part way through I get an error message. I started up my MacBook from the OS-X cd and ran Disk Utility. Selected "Erase Free Space" (7-pass) and after it ran for a few hours, but before it was finished, it quit. This message was displayed: "Disk Utility internal error - Disk Utility has lost its connection with the Disk Management Tool and cannot continue. Please quit and relaunch Disk Utility." I tried rebooting, and the same thing happened. I tried running Disk Repair and found no problems. Any suggestions?

Erasing Free Space Will Definitely Help Me and My Situation. Plus I've deleted or transferred files to an External HD, a ton of files(About 75%). And still the hard drive is reading FULL. The Erase Free Space Option just isn't working for some odd reason. So Erase Free Space Is Definitely What I'm Looking For. Any think you can think of, why it's not working properly?? And thanks for you speedy response also.

Erasing only free space

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